4.2 Driveline Dimension
To accompany the variety of 3 point hitch geometry
available today, the driveline can be too long for
some machines or too short for others. It is very
important that the driveline be free to telescope but
not to bottom out when going through its working
range. If the driveline bottoms out, the bearings
on both the machine and tractor PTO shaft will be
overloaded and fail in a short time.
To determine the proper length of the driveline,
follow this procedure:
1. Attach brush cutter to tractor but do not attach
driveline.
2. Raise cutter until the input shaft is level with
tractor PTO shaft.
3. Measure dimension (A) between locking
grooves on tractor PTO shaft and cutter input
shaft.
4. Measure same dimension (B) on compressed
driveline.
5. If compressed driveline dimension (B) exceeds
the machine dimension (A), driveline must be
cut.
When cutting driveline, follow this procedure:
1. Subtract machine dimension (A) from uncut
driveline dimension (B). This dimension
determines how much too long the driveline is.
2. Add 1 in. (25 mm) to the dimension to be sure
it doesn’t bottom out, to determine cut off
dimension (C).
3. Use a hacksaw to cut dimension (C) from both
ends. Cut both plastic tubes and metal cores.
4. Use a file to remove burrs from cut edges.
5. Assemble shaft.
6. Make sure shaft can telescope freely. If it does
not, separate and inspect for burrs or cuttings
on shaft ends. Be sure it telescopes freely
before installing.
11
